Experimental and computational investigations of sulfur-resistant bimetallic catalysts for reforming of biomass gasification products

Rangan, Meghana; Yung, Matthew M.; Medlin, J. Will

doi:10.1016/j.jcat.2011.06.009

Cited by 22 publications

(16 citation statements)

References 78 publications

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“…Both sulfur and ethylene adsorption are highly favorable in the W-containing sites of W 0. 33 Note that in the experimental work reported here, NiW catalysts were exposed to a higher H 2 S concentration (50 ppm) as compared to the NiRu catalysts in the previous study (5 ppm) [17]. While previous studies have generally shown that higher H 2 S concentrations in this range result in decreased catalyst activity and more rapid deactivation [31], it is important to point out that NiW and NiRu bimetallic catalysts may have different ranges of effective sulfur resistance based on their different mechanisms for sulfur tolerance described below.…”

Section: Sulfur and Ethylene Adsorption On Niw Bimetallic Surfacesmentioning

confidence: 78%

“…In our previous work, we found that the addition of Ru to a Ni catalyst supported on Al 2 O 3 (Ni/Al 2 O 3 ) greatly improved its activity both in the presence as well as the absence of sulfur [17]. As mentioned earlier, ethylene adsorption is favored if there are more unoccupied states above the Fermi level.…”

Section: Electronic Effects On Bindingmentioning

confidence: 86%

“…That is, the strongest ethylene adsorption is observed for the surface that is most dilute in Ru, such that isolated Ru atoms appear to be associated with strong ethylene adsorption. However, catalysts that are highly dilute in Ru will have few of these active sites, a tradeoff remarked upon in a previous contribution [17].…”

Section: Sulfur and Ethylene Adsorption On Ni And Nirumentioning

confidence: 99%

“…In previous work, we used ethylene as a probe molecule to experimentally study the activities of various Ni bimetallic catalysts [17]. We found that C 2 H 4 conversion in both the presence and absence of sulfur is much higher on the NiRu bimetallic catalyst compared to a monometallic Ni catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…The NiRu bimetallic catalyst was also more active for the reforming of ethylene, methane, and benzene in a model synthesis gas stream both in the presence and absence of sulfur. We furthermore reported on preliminary density functional theory (DFT) calculations which indicated that NiRu bimetallics were characterized by stronger binding of ethylene and sulfur, but with promotion of ethylene binding (and subsequent decomposition) being much stronger [17].…”

Section: Introductionmentioning

confidence: 99%

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NiW and NiRu Bimetallic Catalysts for Ethylene Steam Reforming: Alternative Mechanisms for Sulfur Resistance

2012

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Previous investigations of Ni-based catalysts for the steam reforming of hydrocarbons have indicated that the addition of a second metal can reduce the effects of sulfur poisoning. Two systems that have previously shown promise for such applications, NiW and NiRu, are considered here for the steam reforming of ethylene, a key component of biomass derived tars. Monometallic and bimetallic Al 2 O 3 -supported Ni and W catalysts were employed for ethylene steam reforming in the presence and absence of sulfur. The NiW catalysts were less active than Ni in the absence of sulfur, but were more active in the presence of 50 ppm H 2 S. The mechanism for the W-induced improvements in sulfur resistance appears to be different from that for Ru in NiRu. To probe reasons for the sulfur resistance of NiRu, the adsorption of S and C 2 H 4 on several bimetallic NiRu alloy surfaces ranging from 11 to 33 % Ru was studied using density functional theory (DFT). The DFT studies reveal that sulfur adsorption is generally favored on hollow sites containing Ru. Ethylene preferentially adsorbs atop the Ru atom in all the NiRu (111) alloys investigated. By comparing trends across the various bimetallic models considered, sulfur adsorption was observed to be correlated with the density of occupied states near the Fermi level while C 2 H 4 adsorption was correlated with the number of unoccupied states in the d-band. The diverging mechanisms for S and C 2 H 4 adsorption allow for bimetallic surfaces such as NiRu that enhance ethylene binding without accompanying increases in sulfur binding energy. In contrast, bimetallics such as NiSn and NiW appear to decrease the affinity of the surface for both the reagent and the poison.

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Section: Sulfur and Ethylene Adsorption On Niw Bimetallic Surfacesmentioning

confidence: 78%

Section: Electronic Effects On Bindingmentioning

confidence: 86%

Section: Sulfur and Ethylene Adsorption On Ni And Nirumentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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NiW and NiRu Bimetallic Catalysts for Ethylene Steam Reforming: Alternative Mechanisms for Sulfur Resistance

2012

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Bi‐Reforming of Biogas for Hydrogen Production with Sulfur‐Resistant Multimetallic Catalyst

et al. 2023

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A multimetallic sample, NiCeSnRh/Al 2 O 3 , was tested in methane reforming with a CH 4 :H 2 O:CO 2 molar ratio equal to 3:2:1. A very stable methane conversion with the time-on-stream was achieved during 20 h. Dimethyl sulfide served as a model sulfur molecule and a sulfurized sample was also tested. This achieved slightly lower conversion with a stable performance for more than 10 h and a minor but continuous decrease of its activity, after this period. The carbon dioxide conversion was always higher than the methane conversion in agreement with the lower H 2 /CO ratio observed with respect to the theoretical value, 2/1, indicating the sulfur might block the active sites for H 2 O activation. The analysis of the used catalysts showed graphitic and disordered carbon deposits.

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Dispersed and high loading Ni catalyst stabilized in porous SiO2 matrix for substituted natural gas production

et al. 2018

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Experimental and computational investigations of sulfur-resistant bimetallic catalysts for reforming of biomass gasification products

Cited by 22 publications

References 78 publications

NiW and NiRu Bimetallic Catalysts for Ethylene Steam Reforming: Alternative Mechanisms for Sulfur Resistance

NiW and NiRu Bimetallic Catalysts for Ethylene Steam Reforming: Alternative Mechanisms for Sulfur Resistance

Bi‐Reforming of Biogas for Hydrogen Production with Sulfur‐Resistant Multimetallic Catalyst

Dispersed and high loading Ni catalyst stabilized in porous SiO2 matrix for substituted natural gas production

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